Washington - NASA's Orion spaceship made a close pass by the moon and used a gravity assist to whip itself back toward Earth on Monday, marking the start of the return journey for the Artemis-1 mission.
At its nearest point, the uncrewed capsule flew less than 130 kilometers from the moon's surface, testing maneuvers that will be used during later Artemis missions that return humans to the rocky celestial body.
Communication with the capsule was interrupted for 30 minutes when it was behind the far side of the moon, an area more cratered than the near side and first seen by humans during the Apollo era, although they didn't land there.
The European Service Module, which powers the capsule, fired its main engine for more than three minutes to put the gumdrop-shaped Orion on course for home.
'We couldn't be more pleased about how the spacecraft is performing,' Debbie Korth, Orion Program deputy manager, said later.
As spectacular footage flashed on their screens once communication was restored, she told a news conference, 'everybody in the room, we just kind of had to stop and pause, and just really look - 'Wow, we're saying goodbye to the moon.''
Explainer: NASA's New Mega Moon Rocket, Orion Crew Capsule
Monday's maneuver was the last major one of the mission, which began when NASA's mega moon rocket SLS blasted off from Florida on November 16. From start to finish, the journey should last 25½ days.
Orion will now make only slight course corrections until it splashes down in the Pacific Ocean off San Diego on Sunday at 9:40 a.m. local time (1740 GMT). It will then be recovered and hoisted aboard a U.S. Navy ship.
Earlier in the mission, Orion spent about six days in 'distant retrograde orbit' around the moon, meaning at high altitude and traveling opposite the direction the moon revolves around Earth.
A week ago, Orion broke the distance record for a habitable capsule, venturing 450,000 kilometers from Earth.
Once it returns to Earth, Orion will have traveled more than 1.4 million miles, said Mike Sarafin, the Artemis mission manager.
Re-entry into Earth's atmosphere will present a harsh test for the spacecraft's heat shield, which will need to withstand temperatures of around 2,800 degrees Celsius - or about half the temperature of the surface of the sun.
Under the Artemis program - named for the sister of Apollo in Greek mythology - the United States is seeking to build a lasting presence on the moon in preparation for an onward voyage to Mars.
Artemis 2 will involve a crewed journey to the moon, once again without landing.
The first woman and next man are to land on the lunar south pole during Artemis 3, which is set for no sooner than 2025, though likely significantly later given timeline delays.